Male burms, in my experience tend to remain under 12 feet, but that isn't to say that you won't get an exceptional animal. A healthy 12' burm should also be WELL UNDER 100 pounds.

I love burms, and having owned many BCIs and many burms I prefer the burms.

My advice is to get the burm. They are great animals. If you don't power feed him, he should grow at a manageable rate and to a manageable size.

A good feed schedule is one suitable sized prey item every week. Burms, for the most part, are garbage disposals. They will eat and eat and eat and eat and they will use all that food to grow mega fast if you let them. However, one suitable sized prey item every 7 days is not detrimental to the animal. You're not going to be starving him and he will be healthier in the long run.